Method of operating a bi-turbojets polyphasic pump with axial thrust cancellation

ABSTRACT

A pumping device providing direct energy exchange between a working fluid and a pumped fluid, comprising at least a first ejector propelling the working fluid in one direction and at least a second ejector propelling working fluid in a second direction. The axial thrust induced by the jet emitted in the first direction compensates at least partly that of a jet emitted in the second direction by another ejector.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of application Ser. No. 08/758,171,filed on Nov. 25, 1996, now U.S. Pat. No. 5,827,049 which application isContinuation of application Ser. No. 08/445,779, filed on May 22, 1995(now abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and to a device allowing toincrease the pumping and the thrust performance for devices in which aninduced fluid is used for driving another fluid by direct moment andenergy transfers.

2. Description of the Prior Art

U.S. Pat. No. 4,485,518 by FOA describes a method and a device in whicha direct energy transfer is efficiently performed between a primaryfluid or working fluid and a fluid that is to be transferred over acertain distance. The improvement brought by FOA in relation to patentU.S. Pat. No. 3,046,732 by the same claimant consists in splitting theworking fluid into two parts, in ejecting a first part through portslocated on a rotor towards a fluid to be conveyed, and in using thefluid jet resulting from the second part of the working fluid passingthrough a central port for driving the first part of the working fluidand the fluid to be conveyed. This procedure minimizes shear in a fluidat the surface of a mechanical part and therefore possible fluidbackflows which decrease the pumping efficiency of such a device. Thebearings and the thrusts allowing rotation of the rotor are in contactwith the fluid to be conveyed.

The prior art described in FIG. 1 comprises a rotary jet device in whicha working fluid P under pressure is fed through a pipe 1' into a rotor2' in which a major part of the working fluid flows our through ejectors3' located on the rotor in the form of jets having an inclined directionso that the jets obtained cause rotor 2' to rotate. The rotor 2' issupported by a fixed external housing 7' by means for bearings 8'ensuring the rotation of rotor. Another part of the working fluid passesthrough a central pipe 10' prior to being mixed with an auxiliary fluidfed in through ports located in housing 7'. An interaction space 5'allows the mixing of the part derived through ejectors 3' and thepassing of the mixture delivered by the central jet with the primaryfluid K.

Such a device is not useful when the working fluid exhibits a highpressure and when the rotating speed of the rotor is high, because ofthe presence of bearings which wear out very quickly as a result of themotion of rotation and of the power of the jets.

The use of such bearings is inappropriate for applications where thefluids have high energies. In fact, the rotating speed of the rotorcombined with the one-way ejection of fluids having high power valuesleads to a rapid wearing of the bearings and of the thrusts.

Moreover, the presence of particles, for example solid particles such assand, decreases the reliability of such a device.

SUMMARY OF THE INVENTION

The present invention overcomes such drawbacks and notably improved thelife of the parts allowing the rotation of a rotor with respect to ahousing in which it is located when the fluids used have high power.

The object of the present invention is thus a simple, robust andreliable machine for improving the thrust and pumping devices, notablyby preventing the wear of parts stressed by strong axial thrustsresulting from fluids having high energies.

The present invention can notably be used in the field for production ofheavy crudes.

In accordance with the present invention, the device providing thisresult comprises a piece rotating freely about an axis, the piececomprising at least two means for propelling the working fluid, saidpiece being connected to a pipe for feeding in a working fluid underpressure, a fixed housing arranged around said freely rotating piece soas to create a mixing space between said working fluid and a primaryfluid, said piece being fitted with at least one port for feeding saidprimary fluid into the mixing space. The first means propells at leastpart of the working fluid emitted by an injector in a first directionand the second means propells at least part of said working fluidemitted by another injector in a second direction so that the axialthrust induced by a first jet emitted in the first direction compensatesat least partly that substantially a second jet emitted in the seconddirection.

The first means of the second means form respectively an angle and ofsubstantially 180°--with respect to the axis so that the direction ofthe first jet and the direction of the second jet are opposite.

The freely rotating piece is for example supported with respect to theworking fluid feed pipe by means of fluid bearings and thrusts.

The number of means for propelling working fluid is even and can beselected according to at least one characteristic of the working fluid.

The device comprises for example a primary fluid draw-off deviceconnected to the pipe for feeding in the working fluid.

The device can be located inside a casing, and/or between two casingelements.

The dimension and the geometry of the feed ports for feeding in thefluid to be propelled are for example determined from at least onecharacteristic of the primary fluid.

The present invention also relates to a method which allows imparting toa primary fluid a certain energy by direct energy exchange between aworking fluid and the primary fluid. The working fluid is ejected in theform of several subjets substantially simultaneously in a firstdirection and in a second opposite direction so that the thrust inducedby a jet emitted in the first direction balances substantially that of ajet emitted in the second direction.

The subjets are ejected in substantially opposite directions.

The method and the device for implementing the method is particularlywell suited for the pumping of a multiphase fluid comprising a gasphase, a liquid phase and a solid phase, such as sand, and notably thepumping of a petroleum type effluent from a well.

The different advantages provided by the invention include an increasein the life of the rotating pieces, for example by fluids having veryhigh pressure values.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will be clearfrom reading the description hereafter given by way of non limitativeexamples, with reference to the accompanying drawings in which:

FIG. 1 illustrates the prior art constituting patent U.S. Pat. No.4,239,155,

FIG. 2 illustrates a preferred embodiment according to the invention,and

FIG. 3 diagrammatically shows the device used as a booster forpropelling an effluent flowing in a pipe.

FIG. 4 illustrates the device in combination with a fluid pressurizingdevice and a primary fluid source.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 shows an embodiment of the present invention which is animprovement over the prior art cited above, notably by minimizing thewear of the rotating parts.

A device according to the invention is for example located in a casing 1in which circulates a fluid hereafter called a primary fluid to which itis desired to impart a certain energy in order to transfer it from oneplace to another.

The device is supported with respect to casing 1 by means of an annularpiece 2 and comprises an inner or feed pipe 3 into which a working fluidunder pressure coming from an outer source, which is not shown, is fed.A piece 5 having preferably the shape of a cylindrical housing ispositioned for example coaxially with respect to the axis A of feed pipe3. The inside diameter of the cylindrical housing 5 is greater than theoutside diameter of feed pipe 3 so as to create an annular space Ebetween these two pieces. Ports 7 pierced in feed pipe 3 allow theworking fluid to flow towards this annular space E. Connection of piece5 with feed pipe 3 is provided for example by an assembly 6 that canconsist of a fluid bearing and a fluid thrust, this type of bearings andthrusts minimizing the frictions existing between rotating pieces suchas pieces 3 and 5.

Piece 5 also comprises at least two ejection means such as ejectors 8aand 8b, allowing ejection of the working fluid from the annular space Etowards the primary fluid circulating in casing 1.

Piece 5 rotates freely. As a result of this motion of rotation, thefluid jets coming from ejectors 8a and 8b have, for example, the shapeof helicoids that allow the energy to be transferred to the primaryfluid to be propelled.

A fixed cylindrical housing 9 is arranged preferably coaxially to piece5 and is supported with respect thereto for example by means of a piece10 allowing its lower centering and a piece 11 allowing its uppercentering. Piece 5 and housing 9 are positioned so as to create a mixingspace 12. In this space 12, the working fluid being fed in by ejectors8a and 8b in the form of two subfluids F1 and F2 which, have amountswhich are being substantially identical, mix with the primary fluidcirculating in casing 1 and fed into space 12 as described hereafter.Two submixtures having substantially opposite directions of circulationin space 12 are thus obtained.

A piece 15 such as a tubing forms the outer wall of the device. It isprovided with ports 13 and ports 14 located respectively on either sideof the walls of the tubing, and which communicate together by means, forexample, of inserts 16 connecting a port 13 to a port 14. The primaryfluid circulating in casing 1 thus passes through a port 14, an insert16 and a port 13 prior to entering the mixing space 12. The three pieces13, 14 and 16 are preferably aligned.

When the piece 2 intended for supporting the pumping device with respectto the casing is a packing insulating piece 15 from casing 1, thebackflow occurs for example in the annular space 19 contained betweencasing 1 and the working fluid feed pipe 3.

According to another embodiment, piece 2 is a piece intended forcentering tubing 15 in casing 1. The backflow then occurs in the annularspace 1b contained between tubing 15 and feed pipe 3, which can be acoiled tubing.

The two working subfluids F1 and F2 suck in the primary fluid fed intospace 12 and carry it along by forming two submixtures M1 and M2 havingsubstantially opposite directions of circulation.

The submixture M1 flows out for example through one of the ends ofmixing space 12 prior to passing into the space 18 formed by pieces 9and 15. It opens into a pipe 1b connecting spaces 12 and 18 to thecirculation pipe 1.

The submixture M2 flows out at the opposite end with respect to theprevious one, directly, for example, into pipe 1b.

Piece 15 is connected to the central feed pipe 3 of the device forexample by means of a piece 17 forming notably a seal between thedifferent pieces 3, 5, 9, 15 of the device. The layout of these piecesand the seal obtained with piece 17 are such that the working fluidpasses mainly through ejectors 8a and 8b by producing two subfluids F1and F2, and the main part of the submixtures M1 and M2 flows from themixing space 12 to the annular space 18 or directly into pipe 16. Thesubfluids F1 and F2 and the two submixtures M1 and M2 are channelledthereby.

The direction of fluid flow produced respectively by ejectors 8a and 8b,as represented by the arrows representing fluid flows of mixtures M1 andM2, subtends an angle of approximately 180° as illustrated in FIG. 2.The working fluid jets ejected into the mixing space located betweenpieces 5 and 9 by ejectors 8a have a substantially opposite directionwith respect to that of the working fluid jets passing through ejectors8b. This procedure allows a balancing of the fluid drive resulting fromthe high energy of the jets from ejectors 8a having a first directionwith that of the fluids coming from ejectors 8b having a second oppositedirection.

As a result of the angle between the fluid submixtures from ejectors 8aand 8b, and of the motion of rotation of piece 5, the working fluid jetscome out of ejectors 8a and 8b for example in a helical form. These jetstherefore fulfil a function substantially identical to that of themechanical blades commonly used in thrust devices, while avoiding themechanical problems that may be encountered.

The number of working fluid jets having opposite directions and producedby a device according to the invention is preferably an even number.Such a choice imparts symmetry to the device because the subfluid jetsemitted in each direction are identical, which substantially balancesthe thrusts resulting from the power of the working fluid jets such asaxial thrusts.

The number of ejectors 8a, 8b is for example selected according to theworking fluid, for example as a function of its viscosity.

The inner wall of piece 15 located in the vicinity of piece 17 comprisesfor example three parts 15a and 15f.

Part 15a fits the sealing piece 17. It is extended on either side bypart 15b having preferably a rounded shape.

The rounded shape of part 15a is suited for allowing the submixture M1to pass from space 12 to space 18 with a minimum of pressure drop whileavoiding shearing effects.

The use of such a symmetrical system comprising at least two ejectors8a, 8b producing working fluid jets in substantially opposite directionsminimizes the unbalance resulting from the thrust, for example the axialthrust, which can be great when the fluids have high pressure values.

The number of working fluid jets created to propel the primary fluiddepends on the energy to be transmitted to the primary fluid because theoutgoing speed is deliberately limited in order to greatly decreaseabrasive wear phenomena and to avoid cavitation phenomena, bothdetrimental to a good reliability of the device.

The angle of inclination of ejectors 8a and 8b with respect to the axisA of the device can be selected as a function of the rotating speeddesired for the working fluid jets, in order to obtain the optimumenergy efficiency during the energy transfer between the working fluidand the primary fluid.

The working fluid is generally a fluid having a low viscosity inrelation to the viscosity of the primary fluid. The working fluidproportion is selected as a function of the viscosity of the primaryfluid in order to obtain a working fluid and primary fluid mixture thatcan be conveyed without excessive pressure drop linked to the viscosityof the mixture.

The proportion of working fluid fed into the mixing space 12 iscontrolled, for example, by the number of ports 7 located on the feedpipe 3 and by the number of ejectors 8a and 8b.

It is also possible to control the feeding of the primary fluid byselecting the number of ports 13 and 14.

For viscous primary fluids, this procedure is advantageous and allows abetter fluidity of the mixture to be obtained if the working fluidavailable is limited.

The dimension and the geometry for ports 13 and 14 is determined as afunction of the nature of the primary fluid to be propelled and of thepressure of this fluid. For a petroleum type multiphase fluid, it istherefore advisable to take account of the possible presence of solidparticles.

The working fluid can be a fluid of miscible type or not. It can includeproducts such as inhibitors commonly used for example in the petroleumfield, anticorrosion products, antihydrates, products capable ofpreventing the formation of asphaltenes or of any other depositionsresulting notably from changes in pressure and temperature. The presenceof such products improves the reliability of the pumping devices.

The working fluid can be taken from the primary fluid circulating incasing 1.

In this case, the device comprises, for example, a system as illustratedschematically in FIG. 4 for drawing off a certain amount of primaryfluid and for bringing it to a sufficient pressure value so that it canbe used as a working fluid before recycling it.

The primary fluid source 30 provides fluid to a pressurizing device 32which pressurizes the fluid which is inputted as a working fluid.

In another embodiment, the present device can also be positioned at theend for example of a coiled tubing placed in vertical or horizontalpetroleum type effluent wells.

FIG. 3 illustrates an example of the device used as a booster.

The device according to the invention is advantageously used as abooster for conveying petroleum effluents flowing in a pipe, for examplefrom a source such as a well to a processing location.

FIG. 3 shows the device described in FIG. 2 positioned in casing 1 forexample. The device is held up with respect to casing 1 by means such asa packing 20. Casing 1 comprises for example an opening allowing passageof pipe 3 feeding the working fluid coming from an external source.

The device positioned in this way allows energy to be imparted to afluid circulating in the casing for example in the direction shown byarrow P.

The petroleum effluent to be propelled or primary fluid circulating incasing 1 in the direction shown by arrow P for example passes throughthe device as described in FIG. 2, where it acquires a certain amount ofenergy. During this mixing, a direct energy exchange has occurredbetween the working fluid and the primary fluid, the mixture then flowsout at the end 21 of the device with a sufficient energy ensuring itsconveyance to a processing or reception location for example, that isnot shown.

I claim:
 1. A method of imparting energy to a primary fluid, by directenergy exchange with a working fluid within an annular mixing zoneextending along a longitudinal axis of a rotating pumping device,comprising:emitting at least a part of the working fluid from a rotatingjet located within the annular mixing zone at a stationary longitudinallocation relative to a longitudinal axis of rotation of the rotating jetin a first direction substantially parallel to the axis, emitting atleast a part of the working fluid from a rotating jet located within theannular mixing zone at a stationary longitudinal location relative tothe longitudinal axis in a second substantially opposite directionsubstantially parallel to the axis; and wherein the working fluid is fedin a first radial direction toward the rotating jets prior to emissionby the radial jets and the primary fluid is fed in a second radialdirection opposite to the first radial direction into the annular mixingzone; and thrust along the longitudinal axis induced by the first jetemitting the working fluid in the first direction cancels at least partof thrust along the longitudinal axis induced by the second jet emittingthe working fluid in the second direction, and each rotating jet isfurther located at a fixed circumferential location offset radially fromthe longitudinal axis during rotation and at least one part of theworking fluid is taken from the primary fluid, the primary fluid beingpressurized to a sufficient pressure value to function as the workingfluid.
 2. A method as claimed in claim 1 wherein:the primary fluid is apolyphasic fluid.
 3. A method in accordance with claim 2 wherein:theprimary fluid is fed radially inward into the annular mixing zonebetween the jets and the working fluid is fed radially outward.
 4. Amethod in accordance with claim 3 wherein:the working fluid is fedradially outward into the jets which emit the working fluid in the firstand second directions into the annular mixing zone.
 5. A method inaccordance with claim 4 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 6. A method in accordance with claim 2wherein:the polyphasic fluid comprises solid particles.
 7. A method inaccordance with claim 6 wherein:the primary fluid is a petroleumeffluent.
 8. A method in accordance with claim 7 wherein:the primaryfluid is fed radially inward into the annular mixing zone between thejets and the working fluid is fed radially outward.
 9. A method inaccordance with claim 8 wherein:the working fluid is fed radiallyoutward into the jets which emit the working fluid in the first andsecond directions into the annular mixing zone.
 10. A method inaccordance with claim 9 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 11. A method in accordance with claim 6wherein:the primary fluid is fed radially inward into the annular mixingzone between the jets and the working fluid is fed radially outward. 12.A method in accordance with claim 11 wherein:the working fluid is fedradially outward into the jets which emit the working fluid in the firstand second directions into the annular mixing zone.
 13. A method inaccordance with claim 12 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 14. A method in accordance with claim 2wherein:the primary fluid is a petroleum effluent.
 15. A method inaccordance with claim 1 wherein:the primary fluid comprises solidparticles.
 16. A method in accordance with claim 15 wherein:the primaryfluid is fed radially inward into the annular mixing zone between thejets and the working fluid is fed radially outward.
 17. A method inaccordance with claim 16 wherein:the working fluid is fed radiallyoutward into the jets which emit the working fluid in the first andsecond directions into the annular mixing zone.
 18. A method inaccordance with claim 17 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 19. A method in accordance with claim 15wherein:the primary fluid is a petroleum effluent.
 20. A method inaccordance with claim 19 wherein:the primary fluid is fed radiallyinward into the annular mixing zone between the jets and the workingfluid is fed radially outward.
 21. A method in accordance with claim 20wherein:the working fluid is fed radially outward into the jets whichemit the working fluid in the first and second directions into theannular mixing zone.
 22. A method in accordance with claim 21wherein:the working fluid changes direction by an acute angle betweenentering the jets and being emitted by the jets into the annular mixingzone.
 23. A method in accordance with claim 1 wherein:the primary fluidis fed radially inward into the annular mixing zone between the jets andthe working fluid is fed radially outward.
 24. A method in accordancewith claim 23 wherein:the working fluid is fed radially outward into thejets which emit the working fluid in the first and second directionsinto the annular mixing zone.
 25. A method in accordance with claim 24wherein:the working fluid changes direction by an acute angle betweenentering the jets and being emitted by the jets into the annular mixingzone.
 26. A method in accordance with claim 1 wherein:the primary fluidis a petroleum effluent.
 27. A method of imparting energy to a primaryfluid, by direct energy exchange with a working fluid within an annularmixing zone extending alone a longitudinal axis of a rotating pumpingdevice, comprising:emitting at least a part of the working fluid from arotating jet located within the annular mixing zone at a stationarylongitudinal location relative to a longitudinal axis of rotation of therotating jet in a first direction substantially parallel to the axis,emitting at least a part of the working fluid from a rotating jetlocated within the annular mixing zone at a stationary longitudinallocation relative to the longitudinal axis in a second substantiallyopposite direction substantially parallel to the axis; and wherein theworking fluid is fed in a first radial direction toward the rotatingjets prior to emission by the radial jets and the primary fluid is fedin a second radial direction opposite to the first radial direction intothe annular mixing zone; and thrust along the longitudinal axis inducedby the first jet emitting the working fluid in the first directioncancels at least part of thrust along the longitudinal axis induced bythe second jet emitting the working fluid in the second direction, andeach rotating jet is further located at a fixed circumferential locationoffset radially from the longitudinal axis during rotation and at leastone part of the working fluid is taken from the primary fluid, theprimary fluid being pressurized to a sufficient pressure value tofunction as the working fluid.
 28. A method in accordance with claim 27wherein:the polyphasic fluid comprises solid particles.
 29. A method inaccordance with claim 28 wherein:the primary fluid is fed radiallyinward into the annular mixing zone between the jets and the workingfluid is fed radially outward.
 30. A method in accordance with claim 29wherein:the working fluid is fed radially outward into the jets whichemit the working fluid in the first and second directions into theannular mixing zone.
 31. A method in accordance with claim 30wherein:the working fluid changes direction by an acute angle betweenentering the jets and being emitted by the jets into the annular mixingzone.
 32. A method in accordance with claim 28 wherein:the primary fluidis a petroleum effluent.
 33. A method in accordance with claim 32wherein:the primary fluid is fed radially inward into the annular mixingzone between the jets and the working fluid is fed radially outward. 34.A method in accordance with claim 33 wherein:the working fluid is fedradially outward into the jets which emit the working fluid in the firstand second directions into the annular mixing zone.
 35. A method inaccordance with claim 34 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 36. A method in accordance with claim 27wherein:the primary fluid is fed radially inward into the annular mixingzone between the jets and the working fluid is fed radially outward. 37.A method in accordance with claim 36 wherein:the working fluid is fedradially outward into the jets which emit the working fluid in the firstand second directions into the annular mixing zone.
 38. A method inaccordance with claim 37 wherein:the working fluid changes direction byan acute angle between entering the jets and being emitted by the jetsinto the annular mixing zone.
 39. A method in accordance with claim 27wherein:the primary fluid is a petroleum effluent.